1
|
van Neer A, Nachtsheim D, Siebert U, Taupp T. Movements and spatial usage of harbour seals in the Elbe estuary in Germany. Sci Rep 2023; 13:6630. [PMID: 37095305 PMCID: PMC10125962 DOI: 10.1038/s41598-023-33594-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 04/15/2023] [Indexed: 04/26/2023] Open
Abstract
Harbour seals are top predators in the North Sea and regarded as sentinels for ecosystem health. A few hundred also occur in adjacent estuaries, such as the Elbe estuary, Germany. However, only little is known about how these animals use this dynamic tidally influenced habitat, which has been under high anthropogenic pressure for decades. In this context, nine harbour seals (Phoca vitulina) from the Elbe estuary were equipped with biotelemetry devices to track their movements over multiple months. Harbour seal movements were characterised by short trips (trip length outside pupping season for females: 9.0 ± 1.12 km, males: 7.0 ± 1.24 km) as well as small home ranges (median 50% home range for females: 16.3 km2, males: 36.1 km2) compared to harbour seals from marine regions. Within the estuary, the animals utilised the fairway, river branches and tributaries. During the pupping season in June and July, four seals showed strongly reduced trip lengths and durations, increased daily haul out durations as well as smaller home ranges. Even though a continuous exchange with harbour seals from the Wadden Sea likely occurs, most individuals in this study spent the entire deployment duration inside the estuary. This indicates that the Elbe estuary provides a suitable habitat for harbour seals, despite extensive anthropogenic usage, calling for further studies on the consequences of living in such an industrialised habitat.
Collapse
Affiliation(s)
- Abbo van Neer
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Werftstraße 6, 25761, Büsum, Germany
| | - Dominik Nachtsheim
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Werftstraße 6, 25761, Büsum, Germany.
| | - Ursula Siebert
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Werftstraße 6, 25761, Büsum, Germany
| | - Thomas Taupp
- Department of Animal Ecology, Federal Institute of Hydrology (BfG), Am Mainzer Tor 1, 56068, Koblenz, Germany
| |
Collapse
|
2
|
Nachtsheim DA, Johnson M, Schaffeld T, van Neer A, Madsen PT, Findlay CR, Rojano-Doñate L, Teilmann J, Mikkelsen L, Baltzer J, Ruser A, Siebert U, Schnitzler JG. Vessel noise exposures of harbour seals from the Wadden Sea. Sci Rep 2023; 13:6187. [PMID: 37061560 PMCID: PMC10105764 DOI: 10.1038/s41598-023-33283-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 04/11/2023] [Indexed: 04/17/2023] Open
Abstract
The North Sea faces intense ship traffic owing to increasing human activities at sea. As harbour seals (Phoca vitulina) are abundant top predators in the North Sea, it is hypothesised that they experience repeated, high-amplitude vessel exposures. Here, we test this hypothesis by quantifying vessel noise exposures from deployments of long-term sound and movement tags (DTAGs) on nine harbour seals from the Wadden Sea. An automated tool was developed to detect intervals of elevated noise in the sound recordings. An assessment by multiple raters was performed to classify the source as either vessels or other sounds. A total of 133 vessel passes were identified with received levels > 97 dB re 1µPa RMS in the 2 kHz decidecade band and with ambient noise > 6 dB below this detection threshold. Tagged seals spent most of their time within Marine Protected Areas (89 ± 13%, mean ± SD) and were exposed to high-amplitude vessel passes 4.3 ± 1.6 times per day. Only 32% of vessel passes were plausibly associated with an AIS-registered vessel. We conclude that seals in industrialized waters are exposed repeatedly to vessel noise, even in areas designated as protected, and that exposures are poorly predicted by AIS data.
Collapse
Affiliation(s)
- Dominik André Nachtsheim
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Werftstraße 6, 25761, Büsum, Germany.
| | - Mark Johnson
- Aarhus Institute of Advanced Studies, Aarhus University, 8000, Aarhus, Denmark
- Zoophysiology, Department of Biology, Aarhus University, 8000, Aarhus, Denmark
| | - Tobias Schaffeld
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Werftstraße 6, 25761, Büsum, Germany
| | - Abbo van Neer
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Werftstraße 6, 25761, Büsum, Germany
| | - Peter T Madsen
- Zoophysiology, Department of Biology, Aarhus University, 8000, Aarhus, Denmark
| | - Charlotte R Findlay
- Zoophysiology, Department of Biology, Aarhus University, 8000, Aarhus, Denmark
| | - Laia Rojano-Doñate
- Zoophysiology, Department of Biology, Aarhus University, 8000, Aarhus, Denmark
- Marine Mammal Research, Department of Ecoscience, Aarhus University, 4000, Roskilde, Denmark
| | - Jonas Teilmann
- Marine Mammal Research, Department of Ecoscience, Aarhus University, 4000, Roskilde, Denmark
| | - Lonnie Mikkelsen
- Marine Mammal Research, Department of Ecoscience, Aarhus University, 4000, Roskilde, Denmark
- Norwegian Polar Institute, Fram Centre, 9296, Tromsö, Norway
| | - Johannes Baltzer
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Werftstraße 6, 25761, Büsum, Germany
| | - Andreas Ruser
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Werftstraße 6, 25761, Büsum, Germany
| | - Ursula Siebert
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Werftstraße 6, 25761, Büsum, Germany
| | - Joseph G Schnitzler
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Werftstraße 6, 25761, Büsum, Germany
| |
Collapse
|
3
|
Valenzuela-Toro AM, Mehta R, Pyenson ND, Costa DP, Koch PL. Feeding morphology and body size shape resource partitioning in an eared seal community. Biol Lett 2023; 19:20220534. [PMID: 36883314 PMCID: PMC9993223 DOI: 10.1098/rsbl.2022.0534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023] Open
Abstract
Body size and feeding morphology influence how animals partition themselves within communities. We tested the relationships among sex, body size, skull morphology and foraging in sympatric otariids (eared seals) from the eastern North Pacific Ocean, the most diverse otariid community in the world. We recorded skull measurements and stable carbon (δ13C) and nitrogen (δ15N) isotope values (proxies for foraging) from museum specimens in four sympatric species: California sea lions (Zalophus californianus), Steller sea lions (Eumetopias jubatus), northern fur seals (Callorhinus ursinus) and Guadalupe fur seals (Arctocephalus townsendi). Species and sexes had statistical differences in size, skull morphology and foraging significantly affecting the δ13C values. Sea lions had higher δ13C values than fur seals, and males of all species had higher values than females. The δ15N values were correlated with species and feeding morphology; individuals with stronger bite forces had higher δ15N values. We also found a significant community-wide correlation between skull length (indicator of body length), and foraging, with larger individuals having nearshore habitat preferences, and consuming higher trophic level prey than smaller individuals. Still, there was no consistent association between these traits at the intraspecific level, indicating that other factors might account for foraging variability.
Collapse
Affiliation(s)
- Ana M Valenzuela-Toro
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA 95060, USA.,Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560, USA
| | - Rita Mehta
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA 95060, USA
| | - Nicholas D Pyenson
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA 95060, USA.,Department of Paleontology and Geology, Burke Museum of Natural History and Culture, Seattle, WA 98105, USA
| | - Daniel P Costa
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA 95060, USA.,Institute of Marine Sciences, University of California Santa Cruz, Santa Cruz, CA 95064, USA
| | - Paul L Koch
- Department of Earth and Planetary Sciences, University of California Santa Cruz, Santa Cruz, CA 95064, USA
| |
Collapse
|
4
|
Age as a primary driver of the gut microbial composition and function in wild harbor seals. Sci Rep 2022; 12:14641. [PMID: 36030345 PMCID: PMC9420123 DOI: 10.1038/s41598-022-18565-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 08/16/2022] [Indexed: 11/08/2022] Open
Abstract
Dietary changes are the major variation cause in the composition of the gut microbiota. The short lactation phase in phocids provides an exceptional opportunity to explore the microbiota's response to a quick transition from a milk-based to a solid diet. We investigated the effects of age and sex on the gut microbiota of harbor seals in Mexico using rectal and fecal samples from pups and adults. 16S gene sequencing revealed age explains most of the observed variations in microbial composition. Individuals with frequent contact (pups-female adults) have major microbial similarities than those with little or no contact (pups-male adults). Overall, adults and females (regardless of sex and age, respectively) have a greater microbial richness; as seals grow, the core microbiome shrinks, and microbial diversity increases. We found pathways related to milk and chitin digestion in pups' microbiomes, indicating pups were transitioning to a solid diet. An enrichment of routes related to dramatic weight loss and body mass indicated higher metabolic stress in pups in late breeding season, when they are weaned and start intermittent fasting. Our findings highlight the host-microbiome interaction in harbor seals during late breeding season in response to food shifts and metabolic stress.
Collapse
|
5
|
Ruiz-Mar MG, Heckel G, Solana-Arellano E, Schramm Y, García-Aguilar MC, Arteaga MC. Human activities disturb haul out and nursing behavior of Pacific harbor seals at Punta Banda Estuary, Mexico. PLoS One 2022; 17:e0270129. [PMID: 35793316 PMCID: PMC9258837 DOI: 10.1371/journal.pone.0270129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 06/03/2022] [Indexed: 11/23/2022] Open
Abstract
Humans frequently interact with Pacific harbor seals (Phoca vitulina richardii) at Punta Banda Estuary, Baja California, Mexico, due to the high incidence of recreational activities people undertake there. The immediate effect of these interactions is that seals flush to the water, reducing their time on land and, probably, increasing their energy expenditure. On-land observations were used to study the impact of different sources of disturbance on seal behavior and evaluate their effect on the amount of time dedicated to nursing over three pupping seasons, (2015–2017), with 0.58–0.81 disturbance events/hour recorded over the entire sampling period. Terrestrial vehicles were the source with the highest disturbance rate (number of disturbance events/h), followed closely by pedestrians. However, the proportion of seals affected was highest when pedestrians were the disturbance source. Recovery events (seals hauling out after flushing) occurred after 34% of disturbance events, after less than half of which the same number of hauled-out seals as there were prior to the disturbance were observed. Recovery time varied among the years studied, of which 2017 saw the longest recovery time. In addition, pedestrians were the disturbance source with the longest recovery time. Given that resting on land is essential for pup survival, which depends on both the establishment of the mother-pup bond from birth and its maintenance throughout nursing, flushing behavior may have significant implications for the entire colony during the nursing season. We recorded a decrease in nursing duration, which did not return to the same level even after recovery and the resumption of nursing. Terrestrial vehicles were found to be the disturbance source that shortened nursing events most significantly.
Collapse
Affiliation(s)
- María Guadalupe Ruiz-Mar
- Conservation Biology Department, Centro de Investigación Científica y de Educación Superior de Ensenada, Ensenada, Baja California, Mexico
| | - Gisela Heckel
- Conservation Biology Department, Centro de Investigación Científica y de Educación Superior de Ensenada, Ensenada, Baja California, Mexico
- * E-mail:
| | - Elena Solana-Arellano
- Marine Ecology Department, Centro de Investigación Científica y de Educación Superior de Ensenada, Ensenada, Baja California, Mexico
| | - Yolanda Schramm
- Faculty of Marine Sciences, Universidad Autónoma de Baja California, Ensenada, Baja California, Mexico
| | - María C. García-Aguilar
- Biological Oceanography Department, Centro de Investigación Científica y de Educación Superior de Ensenada, Ensenada, Baja California, Mexico
| | - Maria Clara Arteaga
- Conservation Biology Department, Centro de Investigación Científica y de Educación Superior de Ensenada, Ensenada, Baja California, Mexico
| |
Collapse
|
6
|
Iorio-Merlo V, Graham IM, Hewitt RC, Aarts G, Pirotta E, Hastie GD, Thompson PM. Prey encounters and spatial memory influence use of foraging patches in a marine central place forager. Proc Biol Sci 2022; 289:20212261. [PMID: 35232237 PMCID: PMC8889173 DOI: 10.1098/rspb.2021.2261] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Given the patchiness and long-term predictability of marine resources, memory of high-quality foraging grounds is expected to provide fitness advantages for central place foragers. However, it remains challenging to characterize how marine predators integrate memory with recent prey encounters to adjust fine-scale movement and use of foraging patches. Here, we used two months of movement data from harbour seals (Phoca vitulina) to quantify the repeatability in foraging patches as a proxy for memory. We then integrated these data into analyses of fine-scale movement and underwater behaviour to test how both spatial memory and prey encounter rates influenced the seals' area-restricted search (ARS) behaviour. Specifically, we used one month's GPS data from 29 individuals to build spatial memory maps of searched areas and archived accelerometery data from a subset of five individuals to detect prey catch attempts, a proxy for prey encounters. Individuals were highly consistent in the areas they visited over two consecutive months. Hidden Markov models showed that both spatial memory and prey encounters increased the probability of seals initiating ARS. These results provide evidence that predators use memory to adjust their fine-scale movement, and this ability should be accounted for in movement models.
Collapse
Affiliation(s)
- Virginia Iorio-Merlo
- School of Biological Sciences, Lighthouse Field Station, University of Aberdeen, Cromarty, Ross-shire IV11 8YJ, UK
| | - Isla M Graham
- School of Biological Sciences, Lighthouse Field Station, University of Aberdeen, Cromarty, Ross-shire IV11 8YJ, UK
| | - Rebecca C Hewitt
- School of Biological Sciences, Lighthouse Field Station, University of Aberdeen, Cromarty, Ross-shire IV11 8YJ, UK
| | - Geert Aarts
- Wildlife Ecology and Conservation Group and Wageningen Marine Research, Wageningen University and Research, Ankerpark 27, 1781 AG Den Helder, The Netherlands.,Department of Coastal Systems, NIOZ Royal Netherlands Institute for Sea Research, Texel, The Netherlands
| | - Enrico Pirotta
- Centre for Research into Ecological and Environmental Modelling, University of St Andrews, St Andrews, Fife KY16 9LZ, UK.,School of Biological, Earth and Environmental Sciences, University College Cork, Cork, Ireland
| | - Gordon D Hastie
- Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, St Andrews, Fife KY16 8LB, UK
| | - Paul M Thompson
- School of Biological Sciences, Lighthouse Field Station, University of Aberdeen, Cromarty, Ross-shire IV11 8YJ, UK
| |
Collapse
|
7
|
Jimbo M, Kita YF, Kobayashi M, Mitani Y. Intraspecific differences in the diet of Kuril harbor seals (Phoca vitulina stejnegeri) in Erimo, Hokkaido, using DNA barcoding diet analysis. MAMMAL RES 2021. [DOI: 10.1007/s13364-021-00586-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
|
8
|
Abstract
Central place foragers are expected to offset travel costs between a central place and foraging areas by targeting productive feeding zones. Harbour seals (Phoca vitulina) make multi-day foraging trips away from coastal haul-out sites presumably to target rich food resources, but periodic track points from telemetry tags may be insufficient to infer reliably where, and how often, foraging takes place. To study foraging behaviour during offshore trips, and assess what factors limit trip duration, we equipped harbour seals in the German Wadden Sea with high-resolution multi-sensor bio-logging tags, recording 12 offshore trips from 8 seals. Using acceleration transients as a proxy for prey capture attempts, we found that foraging rates during travel to and from offshore sites were comparable to offshore rates. Offshore foraging trips may, therefore, reflect avoidance of intra-specific competition rather than presence of offshore foraging hotspots. Time spent resting increased by approx. 37 min/day during trips suggesting that a resting deficit rather than patch depletion may influence trip length. Foraging rates were only weakly correlated with surface movement patterns highlighting the value of integrating multi-sensor data from on-animal bio-logging tags (GPS, depth, accelerometers and magnetometers) to infer behaviour and habitat use.
Collapse
|
9
|
Chudzinska M, Nabe-Nielsen J, Smout S, Aarts G, Brasseur S, Graham I, Thompson P, McConnell B. AgentSeal: Agent-based model describing movement of marine central-place foragers. Ecol Modell 2021. [DOI: 10.1016/j.ecolmodel.2020.109397] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
|
10
|
Voelker MR, Schwarz D, Thomas A, Nelson BW, Acevedo‐Gutiérrez A. Large-scale molecular barcoding of prey DNA reveals predictors of intrapopulation feeding diversity in a marine predator. Ecol Evol 2020; 10:9867-9885. [PMID: 33005350 PMCID: PMC7520183 DOI: 10.1002/ece3.6638] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 06/27/2020] [Accepted: 06/29/2020] [Indexed: 12/02/2022] Open
Abstract
Predator-prey interactions are critical in understanding how communities function. However, we need to describe intraspecific variation in diet to accurately depict those interactions. Harbor seals (Phoca vitulina) are an abundant marine predator that prey on species of conservation concern. We estimated intrapopulation feeding diversity (variation in feeding habits between individuals of the same species) of harbor seals in the Salish Sea. Estimates of feeding diversity were examined relative to sex, month, and location using a novel approach that combined molecular techniques, repeated cross-sectional sampling of scat, and a specialization metric (within-individual consistency in diet measured by the Proportional Similarity Index ( P S i )). Based on 1,083 scat samples collected from five haul-out sites during four nonsequential years, we quantified diet using metabarcoding techniques and determined the sex of the scat depositor using a molecular assay. Results suggest that intrapopulation feeding diversity was present. Specialization was high over short periods (24-48 hr, P S i = 0.392, 95% CI = 0.013, R = 100,000) and variable in time and space. Females showed more specialization than males, particularly during summer and fall. Additionally, demersal and benthic prey species were correlated with more specialized diets. The latter finding suggests that this type of prey likely requires specific foraging strategies and that there are trade-offs between pelagic and benthic foraging styles for harbor seals. This differential feeding on prey species, as well as between sexes of harbor seals, indicates that predator-prey interactions in harbor seals are complex and that each sex may have a different impact on species of conservation concern. As such, describing intrapopulation feeding diversity may unravel hitherto unknown complex predator-prey interactions in the community.
Collapse
Affiliation(s)
- Madelyn R. Voelker
- Biology DepartmentWestern Washington UniversityBellinghamWAUSA
- Present address:
Ocean Research College AcademyEverettWAUSA
| | - Dietmar Schwarz
- Biology DepartmentWestern Washington UniversityBellinghamWAUSA
| | | | - Benjamin W. Nelson
- Institute for the Oceans and FisheriesUniversity of British ColumbiaVancouverBCCanada
| | | |
Collapse
|
11
|
Smith J, Karpovich S, Horstmann L, McIntyre J, O’Brien DM. Seasonal differences in foraging and isotopic niche width related to body size in Gulf of Alaska harbor seals. CAN J ZOOL 2019. [DOI: 10.1139/cjz-2019-0108] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Harbor seals (Phoca vitulina Linnaeus, 1758) use different foraging strategies based on body size and sex, but this difference can be difficult to evaluate across seasons. We used stable isotope analysis of harbor seal whiskers from 32 individuals to assess seasonal foraging of seals inhabiting tidewater glacial habitat in Southeast Alaska. We analyzed stable isotope ratios from serial sections of whiskers, estimated deposition date for each section, and used mixed models to determine if sex and body size influence stable isotope ratios. Seals were grouped by size (>1.4 m or ≤1.4 m curvilinear length) as a proxy for sexual maturity to describe isotopic differences between groups using standard ellipse corrected area. Mean carbon and nitrogen isotope ratios differed significantly between size classes (p < 0.005), with no effect of sex. Larger seals exhibited a broader isotopic niche in the fall, winter, and spring relative to smaller seals, but not in the summer. Our results suggest that seals using tidewater glacial habitat share common foraging behavior in the summer, while larger seals exhibit more diverse foraging throughout the rest of the year. These results highlight the importance of tidewater glacial habitat for this population of harbor seals during the summer.
Collapse
Affiliation(s)
- Justin Smith
- Alaska Department of Fish and Game, 1300 College Road, Fairbanks, AK 99701, USA
| | - Shawna Karpovich
- Alaska Department of Fish and Game, 1300 College Road, Fairbanks, AK 99701, USA
| | - Lara Horstmann
- College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, 232 Irving II, Fairbanks, AK 99775, USA
| | - Julie McIntyre
- Department of Mathematics and Statistics, University of Alaska Fairbanks, 513 Ambler Lane, Fairbanks, AK 99775, USA
| | - Diane M. O’Brien
- Institute of Arctic Biology, University of Alaska Fairbanks, P.O. Box 757000, Fairbanks, AK 99775-7000, USA
| |
Collapse
|
12
|
Khaldy L, Peleg O, Tocco C, Mahadevan L, Byrne M, Dacke M. The effect of step size on straight-line orientation. J R Soc Interface 2019; 16:20190181. [PMID: 31387484 PMCID: PMC6731515 DOI: 10.1098/rsif.2019.0181] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Moving along a straight path is a surprisingly difficult task. This is because, with each ensuing step, noise is generated in the motor and sensory systems, causing the animal to deviate from its intended route. When relying solely on internal sensory information to correct for this noise, the directional error generated with each stride accumulates, ultimately leading to a curved path. In contrast, external compass cues effectively allow the animal to correct for errors in its bearing. Here, we studied straight-line orientation in two different sized dung beetles. This allowed us to characterize and model the size of the directional error generated with each step, in the absence of external visual compass cues (motor error) as well as in the presence of these cues (compass and motor errors). In addition, we model how dung beetles balance the influence of internal and external orientation cues as they orient along straight paths under the open sky. We conclude that the directional error that unavoidably accumulates as the beetle travels is inversely proportional to the step size of the insect, and that both beetle species weigh the two sources of directional information in a similar fashion.
Collapse
Affiliation(s)
- Lana Khaldy
- Department of Biology, Lund Vision Group, Lund University, Lund, Sweden
| | - Orit Peleg
- Department of Computer Science, BioFrontiers Institute, University of Colorado Boulder, Boulder, CO, USA
| | - Claudia Tocco
- School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - L Mahadevan
- Departments of Organismic and Evolutionary Biology and Physics, School of Engineering and Applied Sciences, Kavli Institute for NanoBio Science and Technology, Harvard University, Cambridge, MA, USA
| | - Marcus Byrne
- School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Marie Dacke
- Department of Biology, Lund Vision Group, Lund University, Lund, Sweden.,School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, South Africa
| |
Collapse
|
13
|
Schwarz D, Spitzer SM, Thomas AC, Kohnert CM, Keates TR, Acevedo‐Gutiérrez A. Large-scale molecular diet analysis in a generalist marine mammal reveals male preference for prey of conservation concern. Ecol Evol 2018; 8:9889-9905. [PMID: 30386584 PMCID: PMC6202700 DOI: 10.1002/ece3.4474] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 07/12/2018] [Accepted: 07/13/2018] [Indexed: 11/12/2022] Open
Abstract
Sex-specific diet information is important in the determination of predator impacts on prey populations. Unfortunately, the diet of males and females can be difficult to describe, particularly when they are marine predators. We combined two molecular techniques to describe haul-out use and prey preferences of male and female harbor seals (Phoca vitulina) from Comox and Cowichan Bay (Canada) during 2012-2013. DNA metabarcoding quantified the diet proportions comprised of prey species in harbor seal scat, and qPCR determined the sex of the individual that deposited each scat. Using 287 female and 260 male samples, we compared the monthly sex ratio with GLMs and analyzed prey consumption relative to sex, season, site, and year with PERMANOVA. The sex ratio between monthly samples differed widely in both years (range = 12%-79% males) and showed different patterns at each haul-out site. Male and female diet differed across both years and sites: Females consumed a high proportion of demersal fish species while males consumed more salmonid species. Diet composition was related to both sex and season (PERMANOVA: R 2 = 27%, p < 0.001; R 2 = 24%, p < 0.001, respectively) and their interaction (PERMANOVA: R 2 = 11%, p < 0.001). Diet differences between males and females were consistent across site and year, suggesting fundamental foraging differences, including that males may have a larger impact on salmonids than females. Our novel combination of techniques allowed for both prey taxonomic and spatiotemporal resolution unprecedented in marine predators.
Collapse
Affiliation(s)
- Dietmar Schwarz
- Department of BiologyWestern Washington UniversityBellinghamWashington
| | - Sara M. Spitzer
- Department of BiologyWestern Washington UniversityBellinghamWashington
- Present address:
Illumina Inc.San DiegoCalifornia
| | - Austen C. Thomas
- Department of Zoology and Marine Mammal Research UnitInstitute for the Oceans and FisheriesUniversity of British ColumbiaVancouverBritish ColumbiaCanada
- Smith‐RootVancouverWashington
| | | | - Theresa R. Keates
- Department of BiologyWestern Washington UniversityBellinghamWashington
- Present address:
Department of Ocean SciencesUniversity of CaliforniaSanta CruzCalifornia
| | | |
Collapse
|
14
|
Tierney KM, Muir GKP, Cook GT, Heymans JJ, MacKinnon G, Howe JA, Xu S, Brownlow A, Davison NJ, Ten Doeschate M, Deaville R. Nuclear reprocessing-related radiocarbon ( 14C) uptake into UK marine mammals. MARINE POLLUTION BULLETIN 2017; 124:43-50. [PMID: 28693808 DOI: 10.1016/j.marpolbul.2017.07.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 05/08/2017] [Accepted: 07/02/2017] [Indexed: 06/07/2023]
Abstract
To evaluate the transfer of Sellafield-derived radiocarbon (14C) to top predators in the UK marine environment, 14C activities were examined in stranded marine mammals. All samples of harbour porpoise (Phocoena phocoena) obtained from the Irish Sea showed 14C enrichment above background. Mammal samples obtained from the West of Scotland, including harbour porpoise, grey seals (Halichoerus grypus) and harbour seals (Phoca vitulina) showed 14C enrichment but to a lesser extent. This study demonstrates, for the first time, enriched 14C is transferred through the marine food web to apex predators as a consequence of ongoing nuclear reprocessing activities at Sellafield. Total Sellafield 14C discharge activity 24months prior to stranding and, in particular, distance of animal stranding site from Sellafield are significant variables affecting individual 14C activity. 14C activities of West of Scotland harbour porpoises suggest they did not forage in the Irish Sea prior to stranding, indicating a high foraging fidelity.
Collapse
Affiliation(s)
- Kieran M Tierney
- Scottish Universities Environmental Research Centre, Rankine Avenue, Scottish Enterprise Technology Park, East Kilbride G75 0QF, Scotland, UK; The Scottish Association for Marine Science, Scottish Marine Institute, Oban PA37 1QA, Scotland, UK.
| | - Graham K P Muir
- Scottish Universities Environmental Research Centre, Rankine Avenue, Scottish Enterprise Technology Park, East Kilbride G75 0QF, Scotland, UK; The Scottish Association for Marine Science, Scottish Marine Institute, Oban PA37 1QA, Scotland, UK
| | - Gordon T Cook
- Scottish Universities Environmental Research Centre, Rankine Avenue, Scottish Enterprise Technology Park, East Kilbride G75 0QF, Scotland, UK
| | - Johanna J Heymans
- The Scottish Association for Marine Science, Scottish Marine Institute, Oban PA37 1QA, Scotland, UK
| | - Gillian MacKinnon
- Scottish Universities Environmental Research Centre, Rankine Avenue, Scottish Enterprise Technology Park, East Kilbride G75 0QF, Scotland, UK
| | - John A Howe
- The Scottish Association for Marine Science, Scottish Marine Institute, Oban PA37 1QA, Scotland, UK
| | - Sheng Xu
- Scottish Universities Environmental Research Centre, Rankine Avenue, Scottish Enterprise Technology Park, East Kilbride G75 0QF, Scotland, UK
| | - Andrew Brownlow
- Scottish Marine Animal Stranding Scheme, SRUC Veterinary Services Drummondhill, Stratherrick Road, Inverness IV2 4JZ, Scotland, UK
| | - Nicholas J Davison
- Scottish Marine Animal Stranding Scheme, SRUC Veterinary Services Drummondhill, Stratherrick Road, Inverness IV2 4JZ, Scotland, UK
| | - Mariel Ten Doeschate
- Scottish Marine Animal Stranding Scheme, SRUC Veterinary Services Drummondhill, Stratherrick Road, Inverness IV2 4JZ, Scotland, UK
| | - Rob Deaville
- Institute of Zoology, Zoological Society of London, Regent's Park, London NW1 4RY, England, UK
| |
Collapse
|
15
|
Cordes LS, O'Corry-Crowe G, Small RJ. Surreptitious sympatry: Exploring the ecological and genetic separation of two sibling species. Ecol Evol 2017; 7:1725-1736. [PMID: 28331583 PMCID: PMC5355204 DOI: 10.1002/ece3.2774] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 12/19/2016] [Accepted: 12/21/2016] [Indexed: 11/18/2022] Open
Abstract
Climate change is having profound impacts on animal populations, and shifts in geographic range are predicted in response. Shifts that result in range overlap between previously allopatric congeneric species may have consequences for biodiversity through interspecific competition, hybridization, and genetic introgression. Harbor seals (Phoca vitulina) and spotted seals (Phoca largha) are parapatric sibling species and areas of co‐occurrence at the edges of their range, such as Bristol Bay, Alaska, offer a unique opportunity to explore ecological separation and discuss potential consequences of increased range overlap resulting from retreating sea ice. Using telemetry and genetic data from 14 harbor seals and six spotted seals, we explored the ecological and genetic separation of the two species by comparing their utilization distributions, distance from haul‐out, dive behavior (e.g., depth, duration, focus), and evidence of hybridization. Firstly, we show that harbor and spotted seals, which cannot be visually distinguished definitively in all cases, haul‐out together side by side in Bristol Bay from late summer to early winter. Secondly, we observed subtle rather than pronounced differences in ranging patterns and dive behavior during this period. Thirdly, most spotted seals in this study remained close to shore in contrast to what is known of the species in more northern areas, and lastly, we did not find any evidence of hybridization. The lack of distinct ecological separation in this area of sympatry suggests that interspecific competition could play an important role in the persistence of these species, particularly if range overlap will increase as a result of climate‐induced range shifts and loss of spotted seal pagophilic breeding habitat. Our results also highlight the added complexities in monitoring these species in areas of suspected overlap, as they cannot easily be distinguished without genetic analysis. Predicted climate‐induced environmental change will likely influence the spatial and temporal extent of overlap in these two sibling species. Ultimately, this may alter the balance between current isolating mechanisms with consequences for species integrity and fitness.
Collapse
Affiliation(s)
- Line S Cordes
- School of Ocean Sciences College of Natural Sciences Bangor University Menai Bridge UK
| | - Gregory O'Corry-Crowe
- Harbor Branch Oceanographic Institute Florida Atlantic University Fort Pierce FL USA
| | - Robert J Small
- Division of Wildlife Conservation Alaska Department of Fish and Game Juneau AK USA
| |
Collapse
|
16
|
Steingass S, Horning M. Individual-based energetic model suggests bottom up mechanisms for the impact of coastal hypoxia on Pacific harbor seal (Phoca vitulina richardii) foraging behavior. J Theor Biol 2017; 416:190-198. [PMID: 28082128 DOI: 10.1016/j.jtbi.2017.01.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 12/20/2016] [Accepted: 01/04/2017] [Indexed: 10/20/2022]
Abstract
Wind-driven coastal hypoxia represents an environmental stressor that has the potential to drive redistribution of gilled marine organisms, and thereby indirectly affect the foraging characteristics of air-breathing upper trophic-level predators. We used a conceptual individual-based model to simulate effects of coastal hypoxia on the spatial foraging behavior and efficiency of a marine mammal, the Pacific harbor seal (Phoca vitulina richardii) on the Oregon coast. Habitat compression of fish was simulated at varying intensities of hypoxia. Modeled hypoxia affected up to 80% of the water column and half of prey species' horizontal habitat. Pacific sand lance (Ammodytes hexapterus), Pacific herring (Clupea pallasii), and English sole (Parophrys vetulus) were selected as representative harbor seal prey species. Model outputs most affected by coastal hypoxia were seal travel distance to foraging sites, time spent at depth during foraging dives, and daily energy balance. For larger seals, English sole was the most optimal prey during normoxia, however during moderate to severe hypoxia Pacific sand lance was the most beneficial prey. For smaller seals, Pacific herring was the most efficient prey species during normoxia, but sand lance became more efficient as hypoxia increased. Sand lance represented the highest increase in foraging efficiency during severe hypoxic events for all seals. Results suggest that during increasing hypoxia, smaller adult harbor seals could benefit by shifting from foraging on larger neritic schooling fishes to foraging closer inshore on less energetically-dense forage fish. Larger adult seals may benefit by shifting from foraging on groundfish to smaller, schooling neritic fishes as hypoxia increases. The model suggests a mechanism by which hypoxia may result in increased foraging efficiency of Pacific harbor seals, and therefore increased rates of predation on coastal fishes on the continental shelf during hypoxic events.
Collapse
Affiliation(s)
- Sheanna Steingass
- Department of Fisheries and Wildlife, Marine Mammal Institute, Oregon State University, Hatfield Marine Science Center, 2030 SE Marine Science Drive, Newport, OR, USA.
| | - Markus Horning
- Department of Fisheries and Wildlife, Marine Mammal Institute, Oregon State University, Hatfield Marine Science Center, 2030 SE Marine Science Drive, Newport, OR, USA; Alaska SeaLife Center, 301 Railway Ave, Seward, AK 99644, USA
| |
Collapse
|
17
|
Giardino GV, Mandiola MA, Bastida J, Denuncio PE, Bastida RO, Rodríguez DH. Travel for sex: Long-range breeding dispersal and winter haulout fidelity in southern sea lion males. Mamm Biol 2016. [DOI: 10.1016/j.mambio.2014.12.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
18
|
Carter MID, Bennett KA, Embling CB, Hosegood PJ, Russell DJF. Navigating uncertain waters: a critical review of inferring foraging behaviour from location and dive data in pinnipeds. MOVEMENT ECOLOGY 2016; 4:25. [PMID: 27800161 PMCID: PMC5080796 DOI: 10.1186/s40462-016-0090-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 10/17/2016] [Indexed: 05/09/2023]
Abstract
In the last thirty years, the emergence and progression of biologging technology has led to great advances in marine predator ecology. Large databases of location and dive observations from biologging devices have been compiled for an increasing number of diving predator species (such as pinnipeds, sea turtles, seabirds and cetaceans), enabling complex questions about animal activity budgets and habitat use to be addressed. Central to answering these questions is our ability to correctly identify and quantify the frequency of essential behaviours, such as foraging. Despite technological advances that have increased the quality and resolution of location and dive data, accurately interpreting behaviour from such data remains a challenge, and analytical methods are only beginning to unlock the full potential of existing datasets. This review evaluates both traditional and emerging methods and presents a starting platform of options for future studies of marine predator foraging ecology, particularly from location and two-dimensional (time-depth) dive data. We outline the different devices and data types available, discuss the limitations and advantages of commonly-used analytical techniques, and highlight key areas for future research. We focus our review on pinnipeds - one of the most studied taxa of marine predators - but offer insights that will be applicable to other air-breathing marine predator tracking studies. We highlight that traditionally-used methods for inferring foraging from location and dive data, such as first-passage time and dive shape analysis, have important caveats and limitations depending on the nature of the data and the research question. We suggest that more holistic statistical techniques, such as state-space models, which can synthesise multiple track, dive and environmental metrics whilst simultaneously accounting for measurement error, offer more robust alternatives. Finally, we identify a need for more research to elucidate the role of physical oceanography, device effects, study animal selection, and developmental stages in predator behaviour and data interpretation.
Collapse
Affiliation(s)
- Matt Ian Daniel Carter
- Marine Biology & Ecology Research Centre, School of Marine Science & Engineering, Plymouth University, PL4 8AA Plymouth, UK
| | - Kimberley A. Bennett
- School of Science, Engineering & Technology, Abertay University, DD1 1HG Dundee, UK
| | - Clare B. Embling
- Marine Biology & Ecology Research Centre, School of Marine Science & Engineering, Plymouth University, PL4 8AA Plymouth, UK
| | - Philip J. Hosegood
- Centre for Coast and Ocean Science & Engineering, School of Marine Science & Engineering, Plymouth University, PL4 8AA Plymouth, UK
| | - Debbie J. F. Russell
- Sea Mammal Research Unit, University of St. Andrews, KY16 8LB St. Andrews, UK
- Centre for Research into Ecological and Environmental Modelling, University of St. Andrews, KY16 9LZ St. Andrews, UK
| |
Collapse
|
19
|
Wilson RP, Liebsch N, Gómez-Laich A, Kay WP, Bone A, Hobson VJ, Siebert U. Options for modulating intra-specific competition in colonial pinnipeds: the case of harbour seals (Phoca vitulina) in the Wadden Sea. PeerJ 2015; 3:e957. [PMID: 26082869 PMCID: PMC4465952 DOI: 10.7717/peerj.957] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2014] [Accepted: 04/24/2015] [Indexed: 11/20/2022] Open
Abstract
Colonial pinnipeds may be subject to substantial consumptive competition because they are large, slow-moving central place foragers. We examined possible mechanisms for reducing this competition by examining the diving behaviour of harbour seals (Phoca vitulina) after equipping 34 seals (11 females, 23 males) foraging from three locations; Rømø, Denmark and Lorenzenplate and Helgoland, Germany, in the Wadden Sea area with time-depth recorders. Analysis of 319,021 dives revealed little between-colony variation but appreciable inter-sex differences, with males diving deeper than females, but for shorter periods. Males also had higher vertical descent rates. This result suggests that males may have higher overall swim speeds, which would increase higher oxygen consumption, and may explain the shorter dive durations compared to females. Intersex variation in swim speed alone is predicted to lead to fundamental differences in the time use of three-dimensional space, which may help reduce consumptive competition in harbour seals and other colonial pinnipeds.
Collapse
Affiliation(s)
- Rory P Wilson
- Swansea Laboratory for Animal Movement, Biosciences, College of Science, Swansea University , Swansea, Wales , UK ; GEOMAR Helmholtz Centre for Ocean Research, Düsternbrooker , Kiel , Germany
| | - Nikolai Liebsch
- Customized Animal Tracking Solutions , Moffat Beach, QLD , Australia
| | - Agustina Gómez-Laich
- Centro Nacional Patagonico-CONICET , Puerto Madryn (U9120ACD), Chubut , Argentina
| | - William P Kay
- Swansea Laboratory for Animal Movement, Biosciences, College of Science, Swansea University , Swansea, Wales , UK
| | - Andrew Bone
- Swansea Laboratory for Animal Movement, Biosciences, College of Science, Swansea University , Swansea, Wales , UK
| | - Victoria J Hobson
- Swansea Laboratory for Animal Movement, Biosciences, College of Science, Swansea University , Swansea, Wales , UK
| | - Ursula Siebert
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover , Büsum , Germany
| |
Collapse
|
20
|
Russell DJF, McClintock BT, Matthiopoulos J, Thompson PM, Thompson D, Hammond PS, Jones EL, MacKenzie ML, Moss S, McConnell BJ. Intrinsic and extrinsic drivers of activity budgets in sympatric grey and harbour seals. OIKOS 2015. [DOI: 10.1111/oik.01810] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Deborah J. F. Russell
- Sea Mammal Research Unit, Univ. of St Andrews; St Andrews, Fife KY16 8LB UK
- Centre for Research into Ecological and Environmental Modelling, Univ. of St Andrews; St Andrews, Fife KY16 9LZ UK
| | - Brett T. McClintock
- National Marine Mammal Laboratory, Alaska Fisheries Science Center, NOAA National Marine Fisheries Service; 7600 Sand Point Way NE Seattle WA 98115 USA
| | - Jason Matthiopoulos
- Inst. of Biodiversity Animal Health and Comparative Medicine, Graham Kerr Building, Univ. of Glasgow; Glasgow G12 8QQ UK
| | - Paul M. Thompson
- Inst. of Biological and Environmental Sciences, Univ. of Aberdeen; Lighthouse Field Station George Street Cromarty IV118YJ UK
| | - Dave Thompson
- Sea Mammal Research Unit, Univ. of St Andrews; St Andrews, Fife KY16 8LB UK
| | - Phil S. Hammond
- Sea Mammal Research Unit, Univ. of St Andrews; St Andrews, Fife KY16 8LB UK
| | - Esther L. Jones
- Sea Mammal Research Unit, Univ. of St Andrews; St Andrews, Fife KY16 8LB UK
| | - Monique L. MacKenzie
- Centre for Research into Ecological and Environmental Modelling, Univ. of St Andrews; St Andrews, Fife KY16 9LZ UK
| | - Simon Moss
- Sea Mammal Research Unit, Univ. of St Andrews; St Andrews, Fife KY16 8LB UK
| | | |
Collapse
|
21
|
Ramasco V, Barraquand F, Biuw M, McConnell B, Nilssen KT. The intensity of horizontal and vertical search in a diving forager: the harbour seal. MOVEMENT ECOLOGY 2015; 3:15. [PMID: 26019871 PMCID: PMC4445568 DOI: 10.1186/s40462-015-0042-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 05/07/2015] [Indexed: 05/12/2023]
Abstract
BACKGROUND Free ranging foraging animals can vary their searching intensity in response to the profitability of the environment by modifying their movements. Marine diving animals forage in a three dimensional space and searching intensity can be varied in both the horizontal and vertical planes. Therefore understanding the relationship between the allocation of searching effort in these two spaces can provide a better understanding of searching strategies and a more robust identification of foraging behaviour from the multitude of foraging indices (FIs) available. We investigated the movement of a widespread marine coastal predator, the harbour seal (Phoca vitulina), and compared two sets of foraging indices reflecting searching intensity respectively in the horizontal plane (displacement speed, extensive vs. intensive movement types, residence time) and in the vertical dimension (time at the bottom of a dive). We then tested how several factors (dive depth, direction of the trip with respect to haul-out site, different predatory tactics, the presence of factors confounding the detection of foraging, and temporal resolution of the data) affected their relationships. RESULTS Overall the indices only showed a very weak positive correlation across the two spaces. However controlling for various factors strengthened the relationships. Resting at sea, a behaviour intrinsically static in the horizontal plane, was found to be strongly negatively related to the time spent at the bottom of the dives, indirectly weakening the relationship between horizontal and vertical foraging indices. Predatory tactic (benthic vs. pelagic) was found to directly affect the relationship. In benthic (as opposed to pelagic) foraging a stronger positive relationship was found between vertical and horizontal indices. CONCLUSIONS Our results indicated that movement responses, leading to an intensification of search, are similar in the two spaces (positive relationship), but additional factors need to be taken into account for this relationship to emerge. Foraging indices measuring residence in the horizontal plane tend to be inflated by resting events at sea, while vertical indices tend to distinguish mainly between periods of activity and inactivity, or of benthic and pelagic foraging. The simultaneous consideration of horizontal and vertical movements, as well as topographic information, allows additional behavioural states to be inferred, providing greater insight into the interpretation of foraging activity.
Collapse
Affiliation(s)
- Virginie Ramasco
- />Institute of Marine Research, Tromsø, Norway
- />University of Tromsø, Tromsø, Norway
| | | | | | | | | |
Collapse
|
22
|
Ramasco V, Biuw M, Nilssen KT. Improving time budget estimates through the behavioural interpretation of dive bouts in harbour seals. Anim Behav 2014. [DOI: 10.1016/j.anbehav.2014.05.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
23
|
McHuron EA, Harvey JT, Castellini JM, Stricker CA, O'Hara TM. Selenium and mercury concentrations in harbor seals (Phoca vitulina) from central California: health implications in an urbanized estuary. MARINE POLLUTION BULLETIN 2014; 83:48-57. [PMID: 24823685 DOI: 10.1016/j.marpolbul.2014.04.031] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Revised: 04/12/2014] [Accepted: 04/16/2014] [Indexed: 06/03/2023]
Abstract
We measured total selenium and total mercury concentrations ([TSe] and [THg]) in hair (n=138) and blood (n=73) of harbor seals (Phoca vitulina) from California to assess variation by geography and sex, and inferred feeding relationships based on carbon, nitrogen, and sulfur stable isotopes. Harbor seals from Hg-contaminated sites had significantly greater [THg], and lesser [TSe] and TSe:THg molar ratios than seals from a relatively uncontaminated site. Males had significantly greater [THg] than females at all locations. Sulfur stable isotope values explained approximately 25% of the variability in [THg], indicating increased Hg exposure for seals with a greater use of estuarine prey species. Decreased [TSe] in harbor seals from Hg-contaminated regions may indicate a relative Se deficiency to mitigate the toxic effects of Hg. Further investigation into the Se status and the potential negative impact of Hg on harbor seals from Hg-contaminated sites is warranted.
Collapse
Affiliation(s)
- Elizabeth A McHuron
- Moss Landing Marine Laboratories, 8272 Moss Landing Road, Moss Landing, CA 95039, USA.
| | - James T Harvey
- Moss Landing Marine Laboratories, 8272 Moss Landing Road, Moss Landing, CA 95039, USA
| | - J Margaret Castellini
- Institute of Marine Science, School of Fisheries and Ocean Sciences, University of Alaska Fairbanks, P.O. Box 757220, Fairbanks, AK 99775-7220, USA
| | - Craig A Stricker
- U.S. Geological Survey, Fort Collins Science Center, Denver Federal Center, Building 21, MS963, Denver, CO 80225, USA
| | - Todd M O'Hara
- Department of Veterinary Medicine, University of Alaska Fairbanks, P.O. Box 755940, Fairbanks, AK 99775-7000, USA
| |
Collapse
|
24
|
Wilson K, Lance M, Jeffries S, Acevedo-Gutiérrez A. Fine-scale variability in harbor seal foraging behavior. PLoS One 2014; 9:e92838. [PMID: 24717815 PMCID: PMC3981695 DOI: 10.1371/journal.pone.0092838] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 02/26/2014] [Indexed: 11/24/2022] Open
Abstract
Understanding the variability of foraging behavior within a population of predators is important for determining their role in the ecosystem and how they may respond to future ecosystem changes. However, such variability has seldom been studied in harbor seals on a fine spatial scale (<30 km). We used a combination of standard and Bayesian generalized linear mixed models to explore how environmental variables influenced the dive behavior of harbor seals. Time-depth recorders were deployed on harbor seals from two haul-out sites in the Salish Sea in 2007 (n = 18) and 2008 (n = 11). Three behavioral bout types were classified from six dive types within each bout; however, one of these bout types was related to haul-out activity and was excluded from analyses. Deep foraging bouts (Type I) were the predominant type used throughout the study; however, variation in the use of bout types was observed relative to haul-out site, season, sex, and light (day/night). The proportional use of Type I and Type II (shallow foraging/traveling) bouts differed dramatically between haul-out sites, seasons, sexes, and whether it was day or night; individual variability between seals also contributed to the observed differences. We hypothesize that this variation in dive behavior was related to habitat or prey specialization by seals from different haul-out sites, or individual variability between seals in the study area. The results highlight the potential influence of habitat and specialization on the foraging behavior of harbor seals, and may help explain the variability in diet that is observed between different haul-out site groups in this population.
Collapse
Affiliation(s)
- Kenady Wilson
- Western Washington University, Department of Biology, Bellingham, Washington, United States of America
- * E-mail:
| | - Monique Lance
- Washington Department of Fish and Wildlife, Wildlife Science Program, Lakewood, Washington, United States of America
| | - Steven Jeffries
- Washington Department of Fish and Wildlife, Wildlife Science Program, Lakewood, Washington, United States of America
| | | |
Collapse
|
25
|
Womble JN, Gende SM. Post-breeding season migrations of a top predator, the harbor seal (Phoca vitulina richardii), from a marine protected area in Alaska. PLoS One 2013; 8:e55386. [PMID: 23457468 PMCID: PMC3573017 DOI: 10.1371/journal.pone.0055386] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Accepted: 12/23/2012] [Indexed: 11/30/2022] Open
Abstract
Marine protected areas (MPAs) are increasingly being used as a conservation tool for highly mobile marine vertebrates and the focus is typically on protecting breeding areas where individuals are aggregated seasonally. Yet movements during the non-breeding season can overlap with threats that may be equally as important to population dynamics. Thus understanding habitat use and movements of species during the non-breeding periods is critical for conservation. Glacier Bay National Park, Alaska, is one of the largest marine mammal protected areas in the world and has the only enforceable protection measures for reducing disturbance to harbor seals in the United States. Yet harbor seals have declined by up to 11.5%/year from 1992 to 2009. We used satellite-linked transmitters that were attached to 37 female harbor seals to quantify the post-breeding season migrations of seals and the amount of time that seals spent inside vs. outside of the MPA of Glacier Bay. Harbor seals traveled extensively beyond the boundaries of the MPA of Glacier Bay during the post-breeding season, encompassing an area (25,325 km2) significantly larger than that used by seals during the breeding season (8,125 km2). These movements included the longest migration yet recorded for a harbor seal (3,411 km) and extended use (up to 23 days) of pelagic areas by some seals. Although the collective utilization distribution of harbor seals during the post-breeding season was quite expansive, there was a substantial degree of individual variability in the percentage of days that seals spent in the MPA. Nevertheless, harbor seals demonstrated a high degree of inter-annual site fidelity (93%) to Glacier Bay the following breeding season. Our results highlight the importance of understanding the threats that seals may interact with outside of the boundaries of the MPA of Glacier Bay for understanding population dynamics of seals in Glacier Bay.
Collapse
Affiliation(s)
- Jamie N Womble
- Department of Fisheries and Wildlife, Marine Mammal Institute, Oregon State University, Hatfield Marine Science Center, Newport, Oregon, United States of America.
| | | |
Collapse
|
26
|
Bajzak CE, Bernhardt W, Mosnier A, Hammill MO, Stirling I. Habitat use by harbour seals (Phoca vitulina) in a seasonally ice-covered region, the western Hudson Bay. Polar Biol 2012. [DOI: 10.1007/s00300-012-1274-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
27
|
Sharples RJ, Moss SE, Patterson TA, Hammond PS. Spatial variation in foraging behaviour of a marine top predator (Phoca vitulina) determined by a large-scale satellite tagging program. PLoS One 2012; 7:e37216. [PMID: 22629370 PMCID: PMC3357409 DOI: 10.1371/journal.pone.0037216] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Accepted: 04/17/2012] [Indexed: 11/19/2022] Open
Abstract
The harbour seal (Phoca vitulina) is a widespread marine predator in Northern Hemisphere waters. British populations have been subject to rapid declines in recent years. Food supply or inter-specific competition may be implicated but basic ecological data are lacking and there are few studies of harbour seal foraging distribution and habits. In this study, satellite tagging conducted at the major seal haul outs around the British Isles showed both that seal movements were highly variable among individuals and that foraging strategy appears to be specialized within particular regions. We investigated whether these apparent differences could be explained by individual level factors: by modelling measures of trip duration and distance travelled as a function of size, sex and body condition. However, these were not found to be good predictors of foraging trip duration or distance, which instead was best predicted by tagging region, time of year and inter-trip duration. Therefore, we propose that local habitat conditions and the constraints they impose are the major determinants of foraging movements. Specifically the distance to profitable feeding grounds from suitable haul-out locations may dictate foraging strategy and behaviour. Accounting for proximity to productive foraging resources is likely to be an important component of understanding population processes. Despite more extensive offshore movements than expected, there was also marked fidelity to the local haul-out region with limited connectivity between study regions. These empirical observations of regional exchange at short time scales demonstrates the value of large scale electronic tagging programs for robust characterization of at-sea foraging behaviour at a wide spatial scale.
Collapse
Affiliation(s)
- Ruth J Sharples
- Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, St Andrews, Scotland, United Kingdom.
| | | | | | | |
Collapse
|
28
|
Skeate ER, Perrow MR, Gilroy JJ. Likely effects of construction of Scroby Sands offshore wind farm on a mixed population of harbour Phoca vitulina and grey Halichoerus grypus seals. MARINE POLLUTION BULLETIN 2012; 64:872-881. [PMID: 22333892 DOI: 10.1016/j.marpolbul.2012.01.029] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2011] [Revised: 01/19/2012] [Accepted: 01/21/2012] [Indexed: 05/31/2023]
Abstract
Scroby Sands offshore wind farm was built close to a haul-out and breeding site for harbour seal, a species of conservation concern. An aerial survey programme conducted during a five-year period spanning wind farm construction, revealed a significant post-construction decline in haul-out counts. Multivariate model selection suggested that the decline was not related to the environmental factors considered, nor did it mirror wider population trends. Although cause and effect could not be unequivocally established, the theoretical basis of hearing in pinnipeds and previous studies suggested that extreme noise (to 257 dB re 1 μ Pa(pp) @ 1m) generated by pile-driving of turbine bases led to displacement of seals. A lack of full recovery of harbour seal during the study was also linked to their sensitivity to vessel activity and/or rapid colonisation of competing grey seal. Any impact of offshore wind farm development upon pinnipeds would be much reduced without pile-driving.
Collapse
Affiliation(s)
- Eleanor R Skeate
- ECON Ecological Consultancy Limited, Norwich Research Park, Colney Lane, Norwich NR4 7UH, UK.
| | | | | |
Collapse
|
29
|
Grigg EK, Allen SG, Craven-Green DE, Klimley AP, Markowitz H, Elliott-Fisk DL. Foraging distribution of Pacific harbor seals (Phoca vitulina richardii) in a highly impacted estuary. J Mammal 2012. [DOI: 10.1644/11-mamm-a-128.1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
|
30
|
Young BG, Loseto LL, Ferguson SH. Diet differences among age classes of Arctic seals: evidence from stable isotope and mercury biomarkers. Polar Biol 2009. [DOI: 10.1007/s00300-009-0693-3] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
31
|
Wearmouth VJ, Sims DW. Sexual segregation in marine fish, reptiles, birds and mammals behaviour patterns, mechanisms and conservation implications. ADVANCES IN MARINE BIOLOGY 2008; 54:107-170. [PMID: 18929064 DOI: 10.1016/s0065-2881(08)00002-3] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Sexual segregation occurs when members of a species separate such that the sexes live apart, either singly or in single-sex groups. It can be broadly categorised into two types: habitat segregation and social segregation. Sexual segregation is a behavioural phenomenon that is widespread in the animal kingdom yet the underlying causes remain poorly understood. Sexual segregation has been widely studied among terrestrial mammals such as ungulates, but it has been less well documented in the marine environment. This chapter clarifies terms and concepts which have emerged from the investigation of sexual segregation in terrestrial ecology and examines how a similar methodological approach may be complicated by differences of marine species. Here we discuss the behavioural patterns of sexual segregation among marine fish, reptile, bird and mammal species. Five hypotheses have been forwarded to account for sexual segregation, largely emerging from investigation of sexual segregation in terrestrial ungulates: the predation risk, forage selection, activity budget, thermal niche-fecundity and social factors hypotheses. These mechanisms are reviewed following careful assessment of their applicability to marine vertebrate species and case studies of marine vertebrates which support each mechanism recounted. Rigorous testing of all hypotheses is lacking from both the terrestrial and marine vertebrate literature and those analyses which have been attempted are often confounded by factors such as sexual body-size dimorphism. In this context, we indicate the value of studying model species which are monomorphic with respect to body size and discuss possible underlying causes for sexual segregation in this species. We also discuss why it is important to understand sexual segregation, for example, by illustrating how differential exploitation of the sexes by humans can lead to population decline.
Collapse
Affiliation(s)
- Victoria J Wearmouth
- Marine Biological Association of the United Kingdom, The Laboratory, Citadel Hill, Plymouth PL1 2PB, United Kingdom
| | | |
Collapse
|
32
|
Mackey BL, Durban JW, Middlemas SJ, Thompson PM. A Bayesian estimate of harbour seal survival using sparse photo‐identification data. J Zool (1987) 2007. [DOI: 10.1111/j.1469-7998.2007.00352.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- B. L. Mackey
- University of Aberdeen Lighthouse Field Station, Cromarty, Ross‐Shire, UK
- Sea Mammal Research Unit, Gatty Marine Laboratory, University of St Andrews, St Andrews, UK
| | - J. W. Durban
- University of Aberdeen Lighthouse Field Station, Cromarty, Ross‐Shire, UK
- Alaska Fisheries Science Center, National Marine Fisheries Service, Seattle, WA, USA
| | - S. J. Middlemas
- University of Aberdeen Lighthouse Field Station, Cromarty, Ross‐Shire, UK
- Fisheries Research Service Freshwater Laboratory, Faskally, Pitlochry, UK
| | - P. M. Thompson
- University of Aberdeen Lighthouse Field Station, Cromarty, Ross‐Shire, UK
| |
Collapse
|
33
|
Males in the shade: habitat use and sexual segregation in the Galápagos sea lion (Zalophus californianus wollebaeki). Behav Ecol Sociobiol 2005. [DOI: 10.1007/s00265-005-0042-7] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
34
|
Field IC, Bradshaw CJA, Burton HR, Sumner MD, Hindell MA. Resource partitioning through oceanic segregation of foraging juvenile southern elephant seals ( Mirounga leonina). Oecologia 2004; 142:127-35. [PMID: 15365810 DOI: 10.1007/s00442-004-1704-2] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2004] [Accepted: 08/03/2004] [Indexed: 10/26/2022]
Abstract
In highly dynamic and unpredictable environments such as the Southern Ocean, species that have evolved behaviors that reduce the effects of intra-specific competition may have a selective advantage. This is particularly true when juveniles face disadvantages when foraging due to morphological or physiological limitation, which is the case for many marine mammals. We tracked the at-sea movements of 48 juvenile southern elephant seals ( Mirounga leonina) between the ages of 1 and 4 years from the population at Macquarie Island using locations derived from recorded light levels. There were significant differences in the total amount of the Southern Ocean covered by the different age-groups. The younger seals used a smaller area than the older seals. On average, the younger individuals also made more trips to sea than the older seals and did not travel as far on each trip. Females spent more time at sea than males and there were no significant differences between the total areas used by male and females. In summary, younger seals remained closer to the island at all times, and they spent more time in more northerly regions that older seals. These differences in behavior created temporal and spatial segregation between juveniles of different ages. Therefore, we suggest that these temporal and spatial separations help to avoid intra-specific competition for resources on land, space on beaches, and at-sea foraging areas. Such modifications of haul-out timing and behavior enable them to exploit a patchy and unpredictable environment.
Collapse
Affiliation(s)
- Iain C Field
- Antarctic Wildlife Research Unit, School of Zoology, Private Bag 05, Hobart, TAS 7001, Australia.
| | | | | | | | | |
Collapse
|
35
|
Andersen SM, Lydersen C, Grahl-Nielsen O, Kovacs KM. Autumn diet of harbour seals (Phoca vitulina) at Prins Karls Forland, Svalbard, assessed via scat and fatty-acid analyses. CAN J ZOOL 2004. [DOI: 10.1139/z04-093] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study used hard-part analyses from scats (n = 117) and stomachs (n = 3) to investigate the diet of high Arctic harbour seals (Phoca vitulina L., 1758) living on Prins Karls Forland, Svalbard, in early autumn. Additionally, it compared the results of fatty-acid analyses of the seals' blubber versus that of potential prey with the findings of the more traditional diet assessment method. Svalbard harbour seals appear to be opportunistic, polyphagous feeders similar to the situation in other parts of their range. Members of the cod-family, and secondarily the sculpin-family, dominated the diet of harbour seals on Svalbard. Small fish comprised most of the diet of the harbour seals; invertebrates appeared to be insignificant. Atlantic cod (Gadus morhua L., 1758) was the most important species in the diet in terms of biomass, whereas polar cod (Boreogadus saida (Lepechin, 1774)) was the most frequently consumed prey. Our comparison between hard-part diet analyses and fatty acids is far from definitive, but it indicates a general influence of the diet on the fatty-acid composition of the inner blubber layer. However, it also suggests systematic selective processes in the incorporation of fatty acids into the blubber. Observed differences between the fatty-acid composition of the different blubber layers and possible differences between sex and age classes warrant further investigation.
Collapse
|
36
|
Lesage V, Hammill MO, Kovacs KM. Long-distance movements of harbour seals (Phoca vitulina) from a seasonally ice-covered area, the St. Lawrence River estuary, Canada. CAN J ZOOL 2004. [DOI: 10.1139/z04-084] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Previous studies of harbour seal (Phoca vitulina L., 1758) movements indicate that this species is relatively sedentary throughout the year. However, few investigations have examined their movements and seasonal distribution patterns in ice-covered areas. This study used spatial analysis of ice data and movement data from harbour seals collected via satellite (n = 7) and VHF radiotelemetry (n = 15) to explore this species' spatial use patterns in a seasonally ice-covered region, the St. Lawrence River estuary, Canada. When solid ice formed within the bays of the estuary, four of the seven satellite-tagged animals (all adult males) left their summer haul-out areas, migrating 266 ± 202 km (range 65–520 km) to over-wintering sites. The seals exhibited preference for areas of light to intermediate ice conditions during the winter months; at least six of the seven seals occupied areas with lighter ice conditions than those that prevailed generally in the study area. Evidence of high abundance of potential prey for harbour seals in the estuary during winter suggests that reduced availability of adequate food resources is not the primary factor which influences the movement and distribution patterns of harbour seals. Movement patterns observed during the ice-free period concur with previously reported harbour seal behaviour; the seals remained near the coast (<6.1–11.0 km from shore) in shallow water areas (<50 m deep in 100% VHF and 90% SLTDRs (satellite-linked time-depth recorders)) and travelled only short distances (15–45 km) from capture sites. None of the VHF- or satellite-tagged seals crossed the 350 m deep Laurentian channel, which suggests that this deep body of water might represent a physical barrier to this coastal population.
Collapse
|
37
|
Thompson PM, Van Parijs S, Kovacs KM. Local declines in the abundance of harbour seals: implications for the designation and monitoring of protected areas. J Appl Ecol 2001. [DOI: 10.1046/j.1365-2664.2001.00571.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|